<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      margin: 0;
      height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      background-color: lightcyan;
    }

    .sea {
      font-size: 10px;
      width: 30em;
      height: 30em;
      background-color: whitesmoke;
      border-radius: 0.5em;
      box-shadow: 0 0.2em 3em rgba(0, 0, 0, 0.2);
      background-image: linear-gradient(
        darkblue,
        rgba(255, 255, 255, 0) 80%,
        rgba(255, 255, 255, 0.5)
      );
      position: relative;
      overflow: hidden;
    }
    
    .sea .wave {
      position: absolute;
      width: 50em;
      height: 50em;
      background-color: var(--color);
      border-radius: 43%;
      bottom: 5em;
      left: calc((30em - 50em) / 2);
      filter: opacity(var(--opacity));
      animation: drift linear infinite;
      animation-duration: calc(var(--delay) * 1s);
    }

    .sea .wave:nth-child(1) {--delay: 5; --color: deepskyblue; --opacity: 0.4}
    .sea .wave:nth-child(2) {--delay: 7; --color: deepskyblue; --opacity: 0.4}
    .sea .wave:nth-child(3) {--delay: 9; --color: orangered; --opacity: 0.1}

    @keyframes drift {
      to {
        transform: rotate(-1turn);
      }
    }

    .sea .title {
      z-index: 1;
      color: white;
      font-size: 24px;
      letter-spacing: 0.4em;
      text-align: center;
      position: relative;
      top: 5em;
    }
  </style>
</head>
<body>
  <figure class="sea">
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <p class="title">THE SEA</p>
  </figure>
</body>
</html>